Autoimmune (idiopathic) thrombocytopenic purpura

How I treat thrombocytopenia in pregnancy

ABSTRACT

Thrombocytopenia is a common hematologic abnormality in pregnancy, encountered in ∼10% of pregnancies. There are many possible causes, ranging from benign conditions that do not require intervention to life-threatening disorders necessitating urgent recognition and treatment. Although thrombocytopenia may be an inherited condition or predate pregnancy, most commonly it is a new diagnosis. Identifying the responsible mechanism and predicting its course is made challenging by the tremendous overlap of clinical features and laboratory data between normal pregnancy and the many potential causes of thrombocytopenia. Multidisciplinary collaboration between hematology, obstetrics, and anesthesia and shared decision-making with the involved patient is encouraged to enhance diagnostic clarity and develop an optimized treatment regimen, with careful consideration of management of labor and delivery and the potential fetal impact of maternal thrombocytopenia and any proposed therapeutic intervention. In this review, we outline a diagnostic approach to pregnant patients with thrombocytopenia, highlighting the subtle differences in presentation, physical examination, clinical course, and laboratory abnormalities that can be applied to focus the differential. Four clinical scenarios are presented to highlight the pathophysiology and treatment of the most common causes of thrombocytopenia in pregnancy: gestational thrombocytopenia, preeclampsia, and immune thrombocytopenia.

Gestational thrombocytopenia: a case-control study of over 3,500 pregnancies

Gestational thrombocytopenia (GT) affects an estimated nine million women annually. Women with GT have recurrent episodes on subsequent pregnancies suggesting that GT is related to a maternal factor rather than a factor unique to the individual pregnancy. We performed a case-control study of over 3 500 pregnancies at a single hospital during 2017. We defined GT as any pregnancy with a platelet count <150 000/µl during the 100 days prior to delivery. We excluded women with platelet counts <50 000/µl or with conditions known to cause thrombocytopenia. GT was present in 12% of pregnancies. The median platelet count at delivery was 134 500/µl in cases versus 208 000/µl in controls, P < 0·0001. During the pregnancy, the platelet count declined 31·8% in cases compared with 18·3% in controls (P < 0·0001) in association with a significant increase in mean platelet volume during each trimester. Among women with GT, platelet counts rapidly increased during the first week postpartum, consistent with a mechanism directly related to high blood flow rates in the gravid uterus. GT, a recurrent condition of at-risk women, is a common haematological disorder of pregnancy. Future research may focus on genetic gain-of-function polymorphisms resulting in increased turnover of platelets uncovered only during periods of high-shear blood flow.

Myeloid-Derived Suppressor Cells in Hematologic Diseases: Promising Biomarkers and Treatment Targets

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of immature myeloid cells that exist at very low numbers in healthy subjects but can expand significantly in malignant, infectious, and chronic inflammatory diseases. These cells are characterized as early-MDSCs, monocytic-MDSCs, and polymorphonuclear-MDSCs and can be studied on the basis of their immunophenotypic characteristics and their functional properties to suppress T-cell activation and proliferation. MDSCs have emerged as important contributors to tumor expansion and chronic inflammation progression by inducing immunosuppressive mechanisms, angiogenesis and drug resistance. Most experimental and clinical studies concerning MDSCs have been mainly focused on solid tumors. In recent years, however, the implication of MDSCs in the immune dysregulation associated with hematologic malignancies, immune-mediated cytopenias and allogeneic hemopoietic stem cell transplantation has been documented and the potential role of these cells as biomarkers and therapeutic targets has started to attract a particular interest in hematology. The elucidation of the molecular and signaling pathways associated with the generation, expansion and function of MDSCs in malignant and immune-mediated hematologic diseases and the clarification of mechanisms related to the circulation and the crosstalk of MDSCs with malignant cells and other components of the immune system are anticipated to lead to novel therapeutic strategies. This review summarizes all available evidence on the implication of MDSCs in hematologic diseases highlighting the challenges and perspectives arising from this novel field of research.

Atorvastatin enhances bone marrow endothelial cell function in corticosteroid-resistant immune thrombocytopenia patients

Impaired BM EPCs were found in corticosteroid-resistant ITP patients. Atorvastatin improved BM EPC quantity and function, representing a novel therapy approach for corticosteroid-resistant ITP patients.

10% liquid human immunoglobulin (KIOVIG®) for immunomodulation in autoimmune disorders

Intravenous immunoglobulins have been used to treat autoimmune disorders (ADs) for over 50 years. The etiologies of various ADs are not fully understood and although intravenous immunoglobulin treatment has proved its immunomodulatory properties, the roles of proposed mechanisms of action also remain a matter of speculation. A systemic search of the literature regarding KIOVIG® (Baxalta US, Inc., MA, USA) use in clinical trials on patients with ADs and a detailed review of retrieved articles revealed eight relevant publications. These articles reported KIOVIG use in multifocal motor neuropathy, chronic inflammatory demyelinating polyneuropathy, idiopathic thrombocytopenic purpura, Kawasaki disease, Guillain–Barré syndrome and other autoimmune and neurologic disorders and showed that KIOVIG is an effective, safe and well-tolerated treatment in the studied populations. Nevertheless, further studies on larger patient cohorts are needed.

Usefulness of Measurement of Reticulated Platelets for Diagnosis of Idiopathic Thrombocytopenic Purpura

Reticulated platelets (RP) and large platelets (LP) were measured by an automated hematology analyzer (modified R-2000) in 287 healthy volunteers and 131 patients with thrombocytopenia or thrombocytosis. RP was significantly higher in patients with idiopathic thrombocytopenic purpura (ITP), especially in active phase, while RP was markedly lower in patients with essential thrombocytosis (ET) or chronic myelocytic leukemia (CML). LP was significantly higher in patients with ITP, especially in active phase, while LP was markedly lower in patients with aplastic anemia (AA), ET, or CML. In ITP, RP and LP were significantly higher in patients positive for anti-glycoprotein (Gp) IIb/IIIa antibody. RP and LP were poorly correlated with platelet-associated IgG (PAIgG). RP and LP were poorly correlated with plasma thrombopoietin levels, and negatively correlated with platelet count. These results show that RP reflects the pathology of thrombocytopenic disorders, and that measurement of RP is useful for the differential diagnosis and analysis of platelet kinetics.

Usefulness of Fully Automated Measurement of Reticulated Platelets Using Whole Blood

Reticulated platelets (RP) were measured with an automated hematology analyzer (modified R-2000) in 287 healthy volunteers and in 212 patients with thrombocytopenia. In healthy volunteers, the RP was 0.48 ± 0.26% in men and 0.48 ± 0.32% in women. No significant difference in the RP values due to gender or age (21-60 years) was observed. Furthermore, the reverse correlation was observed between platelet counts and RP. The RP was high in patients with idiopathic thrombocytopenic purpura (ITP), those with high fibrinogen and fibrin degradation products (FDP), and those with high C-reactive protein (CRP), but low in patients after chemotherapy. The RP was highest in active phase of ITP, and relatively high in the partial remission phase of aplastic anemia. In patients after chemotherapy, the patients had a minimum phase of RP and then a maximum phase of RP before platelet counts increased. RP was significantly high in the maximum phase and significantly low in the minimum phase. The relationships between platelet count and RP were negatively correlated in patients with ITP, high FDP, or high CRP, but were not correlated in patients with aplastic anemia, liver disease, or after chemotherapy. These results show that RP reflects the pathology of thrombocytopenic disorders and the measurement of RP is useful for the differential diagnoses and analysis of platelet kinetics.

High-dose dexamethasone corrects impaired myeloid-derived suppressor cell function via Ets1 in immune thrombocytopenia

Myeloid-derived suppressor cells (MDSCs) are heterogeneous immature cells and natural inhibitors of adaptive immunity. In this study, the MDSC population was evaluated in adult patients with primary immune thrombocytopenia (ITP), where cell-mediated immune mechanisms are involved in platelet destruction. Our data demonstrated that both the numbers and suppressive functions of MDSCs were impaired in the peripheral blood and spleens of patients with ITP compared with healthy control patients. High-dose dexamethasone (HD-DXM) treatment rescued MDSC numbers in patients with ITP. And DXM modulation promoted the suppressive function of MDSCs induced in vitro. Moreover, the expression of interleukin 10 and transforming growth factor β was significantly upregulated in DXM-modulated MDSCs compared with the unmodulated cultures. DXM-modulated MDSCs inhibited autologous CD4(+)T-cell proliferation and significantly attenuated cytotoxic T lymphocyte-mediated platelet lysis, further indicating enhanced control over T-cell responses. Elevated expression of the transcription factor Ets1 was identified in DXM-modulated MDSCs. Transfection of Ets-1 small interfering RNA efficiently blocked regulatory effects of MDSCs, which almost offset the augmentation of MDSC function by DXM. Meanwhile, splenocytes from CD61 knockout mice immunized with CD61(+)platelets were transferred into severe combined immunodeficient (SCID) mouse recipients (C57/B6 background) to induce a murine model of severe ITP. We passively transferred the DXM-modulated MDSCs induced from bone marrow of wild-type C57/B6 mice into the SCID mouse recipients, which significantly increased platelet counts in vivo compared with those receiving splenocyte engraftment alone. These findings suggested that impaired MDSCs are involved in the pathogenesis of ITP, and that HD-DXM corrected MDSC functions via a mechanism underlying glucocorticoid action and Ets1.

Contributions of T lymphocyte abnormalities to therapeutic outcomes in newly diagnosed patients with immune thrombocytopenia

T cell abnormalities have been reported to play an important role in pathogenesis of immune thrombocytopenia (ITP) besides specific autoantibodies towards platelet. The aim of this study was to explore the clinical importance of T lymphocyte subsets in adult patients with newly diagnosed ITP before and after first-line treatment. Elderly ITP patients were also studied and we tried to analyze the relationships between these items and therapeutic outcomes. The patients were treated with intravenous immunoglobulin (IVIG) plus corticosteroids and therapeutic responses were evaluated. As a result, compared with the controls, absolute lymphocyte counts in ITP patients decreased significantly before treatment. After treatment, lymphocyte counts restored to control level regardless of their treatment outcomes. In addition, we observed increased IgG and CD19+ cell expression and decreased CD4+/CD8+ cell ratio in both whole ITP group and elderly group before treatment. After treatment, the increased IgG and CD19+ cell expression could be reduced in both respond and non-respond group regardless of patient age, while CD4+/CD8+ cell ratio could not be corrected in non-respond ITP patients. In non-respond ITP patients, increased CD8+ cell expression was noticed and could not be corrected by first-line treatment. Furthermore, even lower NK cell expression was found in non-respond elderly patients after treatment when compared with that in controls. Our findings suggest that ITP patients usually had less numbers of peripheral lymphocytes and patients with higher levels of CD8+ cells or lower levels of CD4+/CD8+ cell ratio were less likely to respond to first-line treatment. Lower levels of NK cells made therapies in elderly ITP patients even more difficult.

Hematologic manifestations of Helicobacter pylori infection

Helicobacter pylori (H. pylori) is the most common infection in humans, with a marked disparity between developed and developing countries. Although H. pylori infections are asymptomatic in most infected individuals, they are intimately related to malignant gastric conditions such as gastric cancer and gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to benign diseases such as gastritis and duodenal and gastric peptic ulcers. Since it was learned that bacteria could colonize the gastric mucosa, there have been reports in the medical literature of over 50 extragastric manifestations involving a variety medical areas of specialization. These areas include cardiology, dermatology, endocrinology, gynecology and obstetrics, hematology, pneumology, odontology, ophthalmology, otorhinolaryngology and pediatrics, and they encompass conditions with a range of clear evidence between the H. pylori infection and development of the disease. This literature review covers extragastric manifestations of H. pylori infection in the hematology field. It focuses on conditions that are included in international consensus and management guides for H. pylori infection, specifically iron deficiency, vitamin B₁₂ (cobalamin) deficiency, immune thrombocytopenia, and MALT lymphoma. In addition, there is discussion of other conditions that are not included in international consensus and management guides on H. pylori, including auto-immune neutropenia, antiphospholipid syndrome, plasma cell dyscrasias, and other hematologic diseases.

Splenic proliferative lymphoid nodules distinct from germinal centers are sites of autoantigen stimulation in immune thrombocytopenia

To understand more specific abnormalities of humoral autoimmunity, we studied 31 spleens from immune thrombocytopenia (ITP) patients and 36 control spleens. Detailed analysis identified at least 2 different splenic structures accommodating proliferating B cells, classic germinal centers (GCs), and proliferative lymphoid nodules (PLNs). PLNs were characterized by proliferating Ki67+ B cells close to follicular dendritic cells (FDCs) and lacked polarization into dark and light zones. As opposed to cells in GCs, proliferating B cells in PLN lacked expression of Bcl6. In both PLNs and GCs of ITP spleens, the density of T cells was significantly reduced. Both T follicular helper cells (TFH) and regulatory T cells were reduced within PLNs of ITP spleens suggesting a defect of tolerance related to a loss of T-cell control. Within PLNs of ITP, but not controls, abundant platelet glycoprotein (GP) IIb/IIIa autoantigens was found in IgM containing immune complexes tightly bound to FDCs and closely approximated to proliferating B cells. GPIV was found less often, but not in the same PLNs as GPIIb/IIIa. Autoantigens were not found in the GCs of ITP or controls indicating that PLNs are the sites of autoantigen stimulation in ITP potentially related to a lack of control by T cells and/or the present autoantigen.

Low expression of FCGRIIB in macrophages of immune thrombocytopenia-affected individuals

Immune thrombocytopenia (ITP) is an autoimmune disorder described as autoantibody-mediated platelet deterioration. Platelets with affiliated IgG are targeted for exploitation by Fc receptor-mediated phagocytic cellular material within the reticuloendothelial system. The objective of this research is to investigate the relationship between the appearance of FC gamma receptors (FCGR) IIB and IIIA on macrophages and clinicopathological characteristics in ITP patients. FCGRIIB and FCGRIIIA were recognized by immunohistochemistry staining of 62 samples, including regular (n = 20) and ITP (n = 42) samples. Subsequently, the relationship of FC gamma expression levels to ITP progression and clinicopathological characteristics was statistically reviewed. Furthermore, the relationship between Helicobacter pylori (HP) infection and FC gamma expression was analyzed. IHC staining with the coordinated spleen tissue trial samples showed that expression of FCGRIIB on macrophages of ITP patients was tremendously reduced in comparison to the healthy control group. However, no variance was discovered between the two groups with respect to FCGRIIIA expression. There was no substantial correlation among FCGRIIB and FCGRIIIA expression and patient age and gender. Significant differences were found between HP infection and decreased expression of FCGRIIB, while there was no difference with the expression of FCGRIIIA. Lower expression of FCGRIIB is likely involved in the etiology of ITP. HP infection is correlated with decreased expression of FCGRIIB. A rise in FCGRIIB may serve as a therapeutic target for human ITP treatment or possibly as a biomarker for ITP analysis.

Recognition of highly restricted regions in the β-propeller domain of αIIb by platelet-associated anti-αIIbβ3 autoantibodies in primary immune thrombocytopenia

Platelet-associated (PA) IgG autoantibodies play an essential role in primary immune thrombocytopenia (ITP). However, little is known about the epitopes of these Abs. This study aimed to identify critical binding regions for PA anti-αIIbβ3 Abs. Because PA anti-αIIbβ3 Abs bound poorly to mouse αIIbβ3, we created human-mouse chimera constructs. We first examined 76 platelet eluates obtained from patients with primary ITP. Of these, 26 harbored PA anti-αIIbβ3 Abs (34%). Further analysis of 15 patients who provided sufficient materials showed that the epitopes of these Abs were mainly localized in the N-terminal half of the β-propeller domain in αIIb (L1-W235). We could identify 3 main recognition sites in the region; 2 eluates recognized a conformation formed by the W1:1-2 and W2:3-4 loops, 5 recognized W1:2-3, and 4 recognized W3:4-1. The remaining 4 eluates could not be defined by the binding sites. Within these regions, we identified residues critical for binding, including S29 and R32 in W1:1-2; G44 and P45 in W1:2-3; and P135, E136, and R139 in W2:3-4. Of 11 eluates whose recognition sites were identified, 5 clearly showed restricted κ/λ-chain usage. These results suggested that PA anti-αIIbβ3 Abs in primary ITP tended to recognize highly restricted regions of αIIb with clonality.

Is Bone Marrow Examination Justified in Isolated Childhood Thrombocytopenia?

Immune thrombocytopenic purpura (UP) is a common pediatric hematologic disorder. Bone marrow aspiration (BMA) is often performed in children with acute ITP to rule out leukemia, aplastic anemia or other hematologic diseases. However, whether BMA is needed in children with typical and hematological features of acute ITP has been questioned. To determine whether BMA is indicated in acute childhood ITP, samples were examined from 122 patients with the provisional diagnosis of acute ITP attending Hevi Pediatric Teaching Hospital, Duhok/North of Iraq between August 2006 and July 2010. Typical acute ITP was defined as an appearance of well being, no hepatosplenomegaly, no lymphadenopathy, normal Hb, WBC, neutrophil count and peripheral blood smear except for thrombocytopenia. A platelet count of 50 x109/L or lower was the cut-off level. No diagnoses of leukemia or aplastic anemia were revealed in the 122 (100%) children with typical hematologic features of ITP and it was concluded that routine BMA is not needed for children with typical features of acute ITP.

A lower starting dose of eltrombopag is efficacious in Japanese patients with previously treated chronic immune thrombocytopenia

BACKGROUND

Eltrombopag is an oral, non-peptide thrombopoietin receptor agonist that has shown efficacy and safety in chronic immune thrombocytopenia (ITP). However, ethnic differences in eltrombopag exposure have been reported: area under the curve exposure to eltrombopag was 87% greater among ITP patients of East Asian descent than among ITP patients of non-East Asian ITP descent.

OBJECTIVES

To evaluate the efficacy and safety of eltrombopag by using, in Japanese ITP patients, lower starting (12.5 mg) and maximum (50 mg) doses of eltrombopag than the standard starting (50 mg) and maximum (75 mg) doses approved in the USA and Europe.

PATIENTS

We examined 23 Japanese patients with previously treated chronic ITP with a platelet count of < 30,000 μL(-1) in a multicenter study comprising a randomized, double-blind, placebo-controlled phase for 6-week evaluation (15 eltrombopag, and eight placebo) and an open-label phase for 6-month evaluation (23 eltrombopag).

RESULTS AND CONCLUSIONS

The response rate (platelet count of ≥ 50,000 μL(-1) ) at week 6 of the 6-week double-blind phase was 60% in eltrombopag-treated patients and 0% in placebo-treated patients. Ten of 23 patients (43.5%) responded for ≥ 75% of predefined assessment visits during the 6-month open-label phase. Notably, 22% (5/23) of patients responded to 12.5 mg of eltrombopag, which was administered within the first 3 weeks of eltrombopag treatment. Bleeding decreased with eltrombopag treatment as compared with baseline. Eltrombopag was generally well tolerated; one patient experienced a transient ischemic attack on day 9. Eltrombopag (12.5-50 mg) is effective for the management of Japanese patients with chronic ITP (NCT00540423).

Prevalence of diagnosed adult immune thrombocytopenia in the United Kingdom

INTRODUCTION

Data regarding the prevalence of immune thrombocytopenia (ITP) is limited, and is derived from North American population-based analyses. Therefore, the authors conducted the first study outside the United States (US) using the United Kingdom (UK) General Practice Research Database (GPRD) to estimate the adult prevalence of ITP in the UK.

METHODS

This study estimated the diagnosed prevalence of ITP in the adult population in UK using the GPRD from January 1, 1992 to December 31, 2009.

RESULTS

The unadjusted, overall 18-year period prevalence was 50.29/100,000 (95% CI: 48.51, 52.06). The age- and gender-adjusted, overall 18-year period prevalence was 50.00/100,000 (95% CI: 49.20, 50.90). ITP prevalence was lower in adults aged 18-49 years of age (30.09/100,000, 95% CI: 28.27, 31.90) than in older adults aged 50-64 years of age (58.22/100,000, 95% CI: 53.88, 62.57) or ≥65 years of age (93.80/100,000, 95% CI: 88.76, 98.85). Prevalence was higher among females (59.32/100,000, 95% CI: 56.63, 62.01) than in males (40.66/100,000, 95% CI: 38.36, 42.96). Prevalence in the GPRD increased over time (1992 [16.33/100,000, 95% CI: 13.70, 19.00], 2000 [36.93/100,000, 95% CI: 34.50, 39.30], and 2009 [58.49/100,000, 95% CI: 55.80, 61.20]).

CONCLUSION

This new analysis of general practice in the UK provides robust prevalence estimates of diagnosed ITP among adults in Europe. ITP prevalence is higher in women and increases with age and over time.

Immune thrombocytopenia: no longer 'idiopathic'

Immune thrombocytopenia (ITP) is a common hematologic disorder. Its pathogenesis involves both accelerated platelet destruction and impaired platelet production. First-line agents are usually effective initially but do not provide long-term responses. Splenectomy remains an effective long-term therapy, as does rituximab (Rituxan) in a subset of patients. Thrombopoietic agents offer a new alternative, although their place in the overall management of ITP remains uncertain.

Development of corpus atrophic gastritis may be associated with Helicobacter pylori-related idiopathic thrombocytopenic purpura

BACKGROUND

A strict correlation between Helicobacter pylori eradication and an increase in platelet count has previously been reported in patients with chronic idiopathic thrombocytopenic purpura (ITP). To clarify the pathogenesis of H. pylori-induced ITP and the factors predicting the platelet response to H. pylori eradication therapy, we evaluated the markers of atrophic gastritis in ITP patients.

METHODS

The study population comprised 31 H. pylori-infected patients with chronic ITP. After undergoing upper gastrointestinal endoscopy and gastric biopsy, all patients received H. pylori eradication therapy. The effect of H. pylori eradication on the platelet count was evaluated for up to 6-54 months after the therapy. The degree of endoscopic gastric atrophy, histological parameters in the gastric mucosa, and serum pepsinogen (PG) levels were compared between platelet responders and nonresponders to the therapy.

RESULTS

H. pylori was successfully eradicated in all patients and a platelet response was seen in 18 (58%) of these patients. The serum pepsinogen (PG) I/II ratio at pretreatment was significantly lower in responders than in nonresponders. The degree of endoscopic gastric atrophy was significantly more severe in responders than in nonresponders. Furthermore, the levels of histological parameters of activity, inflammation, and atrophy in the gastric corpus, but not in the gastric antrum, were significantly more severe in responders than in nonresponders,.

CONCLUSION

The development of corpus atrophic gastritis may be a suitable condition for inducing thrombocytopenia. Evaluation of the serum, endoscopic, and histological markers of atrophic gastritis may assist in selecting patients with ITP who are more likely to respond to H. pylori eradication therapy.

TPO receptor agonist for chronic idiopathic thrombocytopenic purpura

BACKGROUND

Chronic idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disorder that is characterized predominantly by a low platelet count. Thrombopoietin (TPO) receptor agonists increase production of platelets by stimulating the TPO receptor in people with chronic ITP.

OBJECTIVES

To determine the efficacy and safety of TPO receptor agonists in chronic ITP patients.

SEARCH STRATEGY

We searched MEDLINE (from 1950 to March 2011), EMBASE (from 1974 to March 2011), and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3) to identify all randomized trials in chronic ITP. We also contacted authors of included studies and TPO receptor agonists manufacturers.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing TPO receptor agonists alone, or in combination with other drugs, to placebo, no treatment, other drugs, splenectomy or another TPO receptor agonist in patients with chronic ITP.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened papers, extracted data and assessed the risk of bias in the included studies.

MAIN RESULTS

Six trials with 808 patients were included. Five studies compared TPO receptor agonists with placebo (romiplostim: 100, eltrombopag: 299, placebo: 175); one study compared TPO receptor agonists with standard of care (SOC) (romiplostim: 157; SOC: 77). SOC included a variety of therapies, such as glucocorticoid, anti-D immune globulin, intravenous immune globulin, rituximab, azathioprine, and so on. Overall survival, one of our primary outcomes, was not studied by these RCTs and we could not estimate number needed to treat (NNT). Another primary outcome, improving significant bleeding events, did not reveal any significant differences between the TPO receptor agonists group and the control group (placebo or SOC) (versus placebo risk ratio (RR) 0.48, 95% confidence interval (CI) 0.20 to 1.15; versus SOC RR 0.49, 95% CI 0.15 to 1.63).For secondary outcomes, TPO receptor agonists statistically significantly improved overall platelet response (versus placebo RR 4.06, 95% CI 2.93 to 5.63; versus SOC RR 1.81, 95% CI 1.37 to 2.37), complete response (versus placebo RR 9.29, 95% CI 2.32 to 37.15) and durable response (versus placebo RR 14.16, 95% CI 2.91 to 69.01). There was a significant reduction in overall bleeding events (WHO grades 1 to 4) when compared to placebo (RR 0.78, 95% CI 0.68 to 0.89), but not when compared to SOC(RR 0.97, 95% CI 0.75 to 1.26).Total adverse events (Grades 1 to 5) were not statistically significantly different between the treatment and control groups(both placebo and SOC) (versus placebo RR 1.04, 95% CI 0.95 to 1.15; versus SOC RR 0.97, 95% CI 0.75 to 1.26). Total serious adverse events (Grade 3 and higher adverse events) were increased when patients receiving treatment with SOC (RR 0.61, 95% CI 0.40 to 0.92), but not receiving treatment with placebo (RR 0.92, 95% CI 0.61 to 1.38).There are selective and performance biases because of open-label and inadequate allocation.

AUTHORS' CONCLUSIONS

There was currently no evidence to support that TPO receptor agonists are effective in chronic ITP. Compared to placebo or SOC, despite significantly increased platelet response, there was no evidence to demonstrate that TPO receptor agonists did improve significant bleeding events in chronic ITP. The effect on overall survival awaits further analysis. Although long-term studies are lacking, current data demonstrated adverse effects of TPO receptor agonists were similar to that of placebo and SOC.

Dendritic cells modulate platelet activity in IVIg-mediated amelioration of ITP in mice

Intravenous immunoglobulin (IVIg) is an effective treatment against immune thrombocytopenia (ITP). Previous studies suggested that IVIg exerts this ameliorative role through 2 different leukocyte subsets. Dendritic cells (DCs) modulate the immunosuppression in an adoptive cell transfer model, and phagocytes up-regulate their inhibitory IgG Fc receptors (FcγR)IIB expression and thereby ameliorate the inflammatory response and platelet clearance. However, whether or not regulatory mechanisms exist among DCs, phagocytes, and platelets is still largely unknown. In this study we present findings that IVIg-primed splenic CD11c+ DCs (IVIg-DCs) primarily mediate their anti-inflammatory effects at the level of the platelet rather than the phagocyte. IVIg-DCs did not ameliorate ITP in Fcgr2b−/−, Fcgr3−/−, nor P-Selp−/− mice, implicating the potential involvement of these pathways in IVIg action. As platelets are a component of DC regulatory circuits, these findings may suggest an alternative perspective for the use of IVIg treatment.

Evaluation of bleeding and thrombotic events during long-term use of romiplostim in patients with chronic immune thrombocytopenia (ITP)

BACKGROUND

Romiplostim is a peptibody protein that raises platelet counts during long-term treatment of patients with chronic immune thrombocytopenia (ITP). Clinical outcomes related to increased platelet counts include a reduced risk of bleeding and a potential risk of thrombosis.

OBJECTIVE

To evaluate bleeding and thrombotic events occurring in chronic ITP patients during two phase 3, randomized, placebo-controlled, 24-week studies of romiplostim and during subsequent treatment in an open-label extension study.

PATIENTS/METHODS

In the phase 3 trials, 125 patients were randomized to romiplostim or placebo; romiplostim dose was adjusted to maintain platelet counts of 50-200 x 10(9) L(-1). Patients who completed the phase 3 trials could enroll in the extension study in which all patients received romiplostim.

RESULTS

In the phase 3 trials, a significantly greater percentage of patients treated with placebo (34%) had bleeding adverse events of moderate or greater severity than did patients treated with romiplostim (15%, P = 0.018). In the extension study, the incidence of bleeding adverse events of moderate or greater severity decreased from 23% of patients in the first 24 weeks to 12% after 24-48 weeks, remaining < or = 6% thereafter. The exposure-adjusted incidence of thrombotic events was 0.1 per 100 patient-weeks in the phase 3 studies, and 0.08 per 100 patient-weeks in the extension study where patients received romiplostim for up to 144 additional weeks.

CONCLUSIONS

The incidence and severity of bleeding was decreased in chronic ITP patients treated with romiplostim compared with placebo, and the incidence of thrombotic events was not different between the two groups.

CD20-depleting therapy in autoimmune diseases: from basic research to the clinic

The B lymphocyte-associated antigen CD20 is becoming an important immunotherapy target for autoimmune diseases, although its biological function has not been defined. Besides rheumatoid arthritis, growing experience with B cell-depleting therapy indicates that it may be effective in Sjögren's syndrome, dermatomyositis-polymyositis, systemic lupus erythematosus and some types of vasculitides. However, controlled clinical trials are still lacking for some of these indications. Infection has not been seen as a major limitation to this therapy, but reports of progressive multifocal leukoencephalopathy in an extremely small number of patients are of concern. Here, we review the therapeutic actions of anti-CD20 antibodies, and the recent and ongoing clinical trials with CD20-depleting therapy in autoimmune diseases.

A retrospective analysis of therapeutic responses to two distinct corticosteroids in 259 children with acute primary idiopathic thrombocytopenic purpura

OBJECTIVE

To analyze the responses of pediatric patients with newly-diagnosed acute primary idiopathic thrombocytopenic purpura (ITP) to two distinct corticosteroids.

METHODS

We retrospectively reviewed a cohort of 259 patients with acute ITP diagnosed between 2004 and 2008. Specifically, we compared response rates and adverse effects in patients treated with methylprednisolone or dexamethasone.

RESULTS

Corticosteroids were used as the first-line treatment in all patients with an initial response rate of 96.5%. Choice of the intravenous corticosteroid for treatment did not affect the outcome of patients. The time platelet count maintained at a normal level showed no statistical difference between patients administered with methylprednisolone or dexamethasone. Only minor adverse effects were observed in both groups of patients.

CONCLUSIONS

Both corticosteroids yielded similarly high response rates and minor adverse effects in ITP patients. This should be taken into account when choosing the treatment regimen for children with acute ITP.

Evaluation of bone marrow reticulin formation in chronic immune thrombocytopenia patients treated with romiplostim

Romiplostim is a thrombopoietin receptor agonist that increases platelet counts in patients with chronic immune thrombocytopenia (ITP). Thrombopoietin receptor agonists are reported to increase the risk for reticulin fiber deposition within bone marrow. This report describes bone marrow findings from romiplostim-treated rats, a retrospective analysis of reticulin observed in romiplostim ITP clinical trials, and a prospective clinical study of the effects of romiplostim on bone marrow morphology. In rats, romiplostim produced a dose-dependent increase in bone marrow fibrosis that resolved after treatment withdrawal. Of 271 ITP patients in romiplostim clinical trials, 10 were reported to have reticulin deposition; reticulin grade was increased in 4 of 5 patients with both pretreatment and on-treatment bone marrow results. Reticulin grade often decreased soon after romiplostim discontinuation. In the prospective study, reticulin grade during romiplostim treatment remained within the normal range for all patients and was increased in only 1 of 6 patients with pretreatment and on-treatment bone marrow results. This report suggests that romiplostim produces reversible, dose-dependent bone marrow changes in rats and produces modest increases in bone marrow reticulin in some ITP patients that decrease when therapy is discontinued. These studies were registered at www.clinicaltrials.gov as #NCT00102323, #NCT00102336, #NCT00861224, and #NCT00116688.

Repeated courses of rituximab in chronic ITP: Three different regimens

This study investigated responses to retreatment with rituximab in chronic immune thrombocytopenic purpura (ITP) patients. Treatment with rituximab in chronic ITP patients induces long-lasting responses in approximately 30% of patients but even these patients may relapse. Twenty patients who had achieved a response to rituximab and relapsed were retreated with rituximab (375 mg/m(2)x 4); this data was analyzed retrospectively. Subsequently, 16 patients were prospectively randomized to receive rituximab with cyclophosphamide, vincristine and prednisone (R-CVP) or double dose rituximab (DDR). Retreatment with standard dose rituximab demonstrated responses similar to initial rituximab treatment in 15 of 20 patients. Neither of the two more intensive regimens (R-CVP, DDR) induced responses in any patient who had previously failed to respond to rituximab nor induced substantially longer-lasting responses among previous responders. No additional toxicity was noted with the DDR regimen, whereas R-CVP was not well tolerated. These results suggest that retreatment with standard dose rituximab induces similar responses in 75% of previously responding patients and is well tolerated. Neither combining rituximab with CVP nor doubling the dose of rituximab increased the response rate.

Case ReportInduction of T-cell Tolerance in a Patient with Idiopathic Thrombocytopenic Purpura by Single Injection of Humanized Monoclonal Antibody to CD40 Ligand

Normal B cells can be induced to express immune costimulatory molecules by activated T cells, and activated CD4 T cells can express CD40 ligand, a molecule that can engage CD40 on the B-cell surface. CD40-CD40 ligand interaction plays an important role in the pathology of certain autoimmune diseases. We report a patient with chronic idiopathic thrombocyopenic purpura (ITP) who was effectively treated with a single injection of humanized monoclonal antibody to CD40 ligand (E6040). The patient was refractory to steroid therapy, and had baseline platelet counts below 30 x 10(9)/l during the 3-month period before antibody treatment. The patient's platelet counts have increased to more than 100 x 10(9)/l long-term after E6040 administration. Platelet-associated IgG was decreased with thrombocytosis. Compared with the initial period of E6040 administration, the number of anti-GPIIb/IIIa antibody-producing B cells decreased, and proliferative response of autoreactive T cells to GPIIb/IIIa was also improved. A single injection of humanized monoclonal antibody to CD40 ligand may induce T-cell tolerance in patients with ITP.

Late side effects of high-dose steroid therapy on skeletal system in children with idiopathic thrombocytopenic purpura

Corticosteroids have been widely used in the treatment of idiopathic thrombocytopenic purpura (ITP). We evaluated the late side effects of high-dose methylprednisolone (HDMP) therapy on bone metabolism in children with ITP. Twenty-eight children with acute ITP treated with HDMP (30 mg/kg/d for 3 d then 20 mg/kg/d for 4 d) and 28 controls were enrolled in the study. Bone mineral density (BMD), urinary calcium creatinine ratio, urinary levels of deoxypyridinoline, serum levels of calcium, phosphate, parathyroid hormone, total alkaline phosphatase, and bone-specific alkaline phosphatase were measured in both groups. Magnetic resonance imaging of the femoral head was performed only in study group. The mean levels of serum phosphate, parathyroid hormone, urinary deoxypyridinoline, and calcium creatinine ratio were significantly increased in the study group. There was no significant difference between the 2 groups in terms of serum calcium, total alkaline phosphatase, bone-specific alkaline phosphatase, and BMD values. There was a statistically significant negative correlation between cumulative steroid dose and BMD values in study group (r = -0.379). Osteonecrosis was observed in 3 of 25 patients by magnetic resonance imaging. In conclusion, HDMP therapy, especially in high cumulative doses, increases the bone resorption and may cause osteonecrosis in children with ITP.

Prediction of response to splenectomy in patients with idiopathic thrombocytopenic purpura

BACKGROUND

Chronic immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by destruction of opsonized platelets in the reticuloendothelial system, particularly the spleen, and by resulting low platelet counts. Splenectomy is the standard second-line treatment for patients with ITP who do not respond to corticosteroids. In the present study we determined predictive factors for the response of patients with ITP to splenectomy.

MATERIALS AND METHODS

For thirty-one patients with ITP referred from the Hematology Department of Shariati Hospital, open surgical splenectomy was performed between February 2002 and December 2004. All potentially important variables of response were collected and analyzed to determine predictive parameters.

RESULTS

Older patients (>52) responded less positively than younger patients (<52) to splenectomy (p<0.01). Likewise, patients with a sustained remission after splenectomy had a significantly shorter interval of diagnosis of ITP to splenectomy (p<0.05) and shorter duration of corticosteroid therapy before splenectomy (p<0.05).

CONCLUSIONS

This study confirms that splenectomy is an effective treatment for patients with ITP. Our findings highlight age as the major predictive factor of long-term response to splenectomy in patients with ITP.

Cost-effectiveness of Treatment for Acute Childhood Idiopathic Thrombocytopenic Purpura (ITP) – a Systematic Review

The cost-effectiveness of treatment for acute paediatric idiopathic thrombocytopenic purpura (ITP) was assessed to provide evidence for health-care decision making and rational drug use. A systematic review of studies published between 1980 and 7 September 2007 on the clinical effects and economic profiles of treating ITP was undertaken. The quality of the studies was critically appraised and checklists were developed to assess methodological quality and transferability to the Chinese setting. Out of 174 studies, five (one Chinese; four USA) satisfied all the predefined criteria for inclusion and form the basis of this report. Methodological quality of most of the foreign studies was high, but transferability to other countries was low. Use of steroids provided additional life years and was cost-effective compared with intravenous immunoglobulin G and anti-D immunoglobulin. In comparison, the quality of the Chinese studies was low and long-term research rare. It was difficult to compare cost-effectiveness in different health-care settings and no life-time economic evaluations were available.

Efficacy of romiplostim in patients with chronic immune thrombocytopenic purpura: a double-blind randomised controlled trial

BACKGROUND

Chronic immune thrombocytopenic purpura (ITP) is characterised by accelerated platelet destruction and decreased platelet production. Short-term administration of the thrombopoiesis-stimulating protein, romiplostim, has been shown to increase platelet counts in most patients with chronic ITP. We assessed the long-term administration of romiplostim in splenectomised and non-splenectomised patients with ITP.

METHODS

In two parallel trials, 63 splenectomised and 62 non-splenectomised patients with ITP and a mean of three platelet counts 30x10(9)/L or less were randomly assigned 2:1 to subcutaneous injections of romiplostim (n=42 in splenectomised study and n=41 in non-splenectomised study) or placebo (n=21 in both studies) every week for 24 weeks. Doses of study drug were adjusted to maintain platelet counts of 50x10(9)/L to 200x10(9)/L. The primary objectives were to assess the efficacy of romiplostim as measured by a durable platelet response (platelet count > or =50x10(9)/L during 6 or more of the last 8 weeks of treatment) and treatment safety. Analysis was per protocol. These studies are registered with ClinicalTrials.gov, numbers NCT00102323 and NCT00102336.

FINDINGS

A durable platelet response was achieved by 16 of 42 splenectomised patients given romplostim versus none of 21 given placebo (difference in proportion of patients responding 38% [95% CI 23.4-52.8], p=0.0013), and by 25 of 41 non-splenectomised patients given romplostim versus one of 21 given placebo (56% [38.7-73.7], p<0.0001). The overall platelet response rate (either durable or transient platelet response) was noted in 88% (36/41) of non-splenectomised and 79% (33/42) of splenectomised patients given romiplostim compared with 14% (three of 21) of non-splenectomised and no splenectomised patients given placebo (p<0.0001). Patients given romiplostim achieved platelet counts of 50x10(9)/L or more on a mean of 13.8 (SE 0.9) weeks (mean 12.3 [1.2] weeks in splenectomised group vs 15.2 [1.2] weeks in non-splenectomised group) compared with 0.8 (0.4) weeks for those given placebo (0.2 [0.1] weeks vs 1.3 [0.8] weeks). 87% (20/23) of patients given romiplostim (12/12 splenectomised and eight of 11 non-splenectomised patients) reduced or discontinued concurrent therapy compared with 38% (six of 16) of those given placebo (one of six splenectomised and five of ten non-splenectomised patients). Adverse events were much the same in patients given romiplostim and placebo. No antibodies against romiplostim or thrombopoietin were detected.

INTERPRETATION

Romiplostim was well tolerated, and increased and maintained platelet counts in splenectomised and non-splenectomised patients with ITP. Many patients were able to reduce or discontinue other ITP medications. Stimulation of platelet production by romiplostim may provide a new therapeutic option for patients with ITP.

Unusual presentation of chronic idiopathic thrombocytopenic purpura

A snakebite victim presented with normal clotting profile and a low platelet count. A routine CBC in his past records (February 2004) showed a platelet count of 20,000/microlitre, but the patient was not symptomatic. We report a case of chronic idiopathic thrombocytopenic purpura, incidentally found in a patient presenting with snakebite. The patient also has acquired primary testicular failure. After the diagnosis the patient was on regular follow up. He caused trauma to the right external auditory canal and perforated his tympanic membrane. His left tympanic membrane was also scarred and retracted. Establishing a diagnosis of an ITP early is important so that the patient can take precaution to avoid undue trauma and monitor proper follow up.